The present invention relates to a power feeding apparatus for a network hub installed within a network communication complex, and a network communication system that uses said power feeding apparatus.
There are two types of hubs commonly used in a network communication complex. One type of hub is such a hub as works on a power fed through an AC/DC power adapter connected to a commercial power supply. The other type of hub is such a hub as works on the “Power Over Ethernet (POE)” (Registered trademark). In the latter practice, the power is fed through a communication cable (Ethernet Cable) connected to a POE-compliant power-feeding hub (Ethernet is a registered trademark).
A hub working on the power fed from an AC/DC power adapter connected to a commercial power supply (herein after this type of hub is referred to as an ordinary hub) becomes disabled for communication relaying function (the hub function) if the commercial power supply fails, because a power supply failure causes an interruption in the power feeding to the hub. Therefore, a network communication system that uses the ordinary hub for communication relaying encounters such a problem that the system will be disabled from communicating because the ordinary hub will lose its communication relaying function if a commercial power supply failure occurs.
The ordinary hub on the other hand requires being installed near to the distribution facility of a commercial power supply. Locational consideration is required.
A POE-compliant power-receiving hub that works on the power fed from a POE-compliant power-feeding hub through a communication cable may be installed in a place where a commercial power supply is not available. However, the length of the communication cable acceptable to the system in this usage is limited. The POE-compliant power-receiving hub must be installed within an area of which distance from the POE-compliant power-feeding hub is not greater than 100 m.
Therefore, a network communication system that intends to relay communications using said POE-compliant power-receiving hub encounters such a designing problem that the system must be configured so that the hub should be located always within a limited area.
Further, in a POE-compliant power-feeding hub that works on a commercial power supply, a failure in a commercial power causes the hub to lose its power feeding function and communications relaying function. This loss of functions develops to the failure in the power feeding to a POE-compliant power-receiving hub that is dependent to said POE-compliant power-feeding hub causing an interruption in the communications relaying. This is a problem in that the communication function in a network communication system is disabled.
Where the system uses a POE-compliant power-feeding hub that works on an uninterruptible power supply apparatus having a built-in power storage device, said POE-compliant power-feeding hub and said POE-compliant power-receiving hub can work without interruption of their power reception from the uninterruptible power supply apparatus. Then, the system can maintain communication relaying.
As stated above however, the length of the communication cable acceptable to the system configuration is limited. Said POE-compliant power-receiving hub must be installed within an area of which distance from a POE-compliant power-feeding hub is not greater than 100 m. Therefore, a network communication system that intends to relay communications using such POE-compliant power-receiving hub encounters a designing problem such that the system must be configured so that the hub should be located always within a limited area.
Moreover, the uninterruptible power supply apparatus is expensive, which increases problematically the cost of a network communication system.
For instance, these prior arts are described in JP 9-261264 A and JP 2004-171558 A.